The objective of this proposal is to continue our study on antigen markers which may be useful in the detection of prostate cancer. A new, specific and sensitive solid-phase immunofluorescence assay for acid phosphatase is to be evaluated for its potential value in the early diagnosis of prostate cancer. A prostate-specific antigen has been purified to homogeneity. Xenoantisera have been raised against the prostate antigen and the specificity of the antisera will be determined. Initial data indicate that this antigen may be of potential use in identifying prostate cancer patients. A new sensitive immunoassay, such as radioimmunoassay or enzyme immunoassay, will be developed and evaluated. In addition, a prostate tumor-specific antigen has been demonstrated and antiserum against it has been produced in non-human primates (baboon). Isolation, purification and characterization of this prostate cancer antigen will be performed. Furthermore, a prostate acid phosphatase-binding globulin has been isolated from normal human serum by affinity chromatography using purified prostatic acid phosphatase. Its potential clinical application in prostate tumor radiolocalization and immunotherapy will be studied. Finally, an immunoassay for measurement of serum ribonuclease is being developed, as purification of two prostatic ribonucleases has been achieved.